Campaign manager Matt David said Huntsman will announce his withdrawal at an event in Myrtle Beach, S.C. Huntsman will endorse Mitt Romney, whom he believes is the best candidate to beat President Barack Obama in November, campaign officials said.

The former Utah governor placed third in last week’s New Hampshire primary despite devoting most of his campaign resources to the state. He had already acknowledged that expectations for him in South Carolina’s primary this week will be “very low.”

Word of the Huntsman withdrawal came on the same day The State, South Carolina’s largest newspaper, endorsed him for president.

The endorsement said there were “two sensible, experienced grownups in the race,” referring to Romney and Huntsman. But it said Huntsman “is more principled, has a far more impressive resume and offers a significantly more important message.”

Although Huntsman was viewed as having little traction in South Carolina, his endorsement of Romney could give the former Massachusetts governor, who leads in state polls, even more of the look of inevitability.

The move comes as pressure has been increasing on Texas Gov. Rick Perry to leave the race in order to allow South Carolina’s influential social conservatives to unify behind either former Pennsylvania Sen. Rick Santorum or former House Speaker Newt Gingrich.

Huntsman’s resume suggested he could be a major contender for the GOP nomination: businessman, diplomat, governor, veteran of four presidential administrations, an expert on China and on foreign trade. With a personal fortune based on his family’s global chemical company, he could be a late entry into the nomination contest without necessarily hobbling his campaign.

Yet Huntsman was almost invisible in a race often dominated by Romney, a fellow Mormon. One reason was timing. For months, Romney and other declared or expected-to-declare candidates drew media attention and wooed voters in early primary states. Huntsman, meanwhile, was half a world away, serving as ambassador to China until he resigned in late April. Nearly two more months would pass before his kickoff speech on June 22 in the shadow of the Statue of Liberty.

To distinguish his candidacy in a crowded field, Huntsman positioned himself as a tax-cutting, budget-balancing chief executive and former business executive who could rise above partisan politics. That would prove to be a hard sell to the conservatives dominating the early voting contests, especially in an election cycle marked by bitter divisions between Republicans and Democrats and a boiling antipathy for President Barack Obama.

Huntsman also tried to offer a different tenor, promising a campaign marked by civility. “I don’t think you need to run down somebody’s reputation in order to run for the office of president,” he said.

While Huntsman was often critical of his former boss – he joined those saying Obama had failed as a leader – and occasionally jabbed at Romney, he spent more of his time in debates pushing his own views for improving the economy than thumping the president or his opponents.

In light of his work in the Obama administration, Republicans seemed wary of Huntsman. While he cast his appointment in August 2009 as U.S. ambassador to China as answering the call to serve his country, his critics grumbled that he had in fact been working on behalf of the opposition.

Huntsman was conservative in matters of taxes and the reach of the federal government, but he was out of step with most conservatives in his support of civil unions for gay couples. On matters of science, he poked fun at his skeptical rivals in a pre-debate tweet: “To be clear. I believe in evolution and trust scientists on global warming. Call me crazy.”

In the end, Huntsman didn’t seem to register, crazy or otherwise, with Republicans looking for an alternative to Romney or a winner against Obama. The former Utah governor was routinely at the bottom of national polls, barely registering at 1 or 2 percent, a reflection of the faint impression he made in the GOP debates.

His campaign put all its emphasis on the New Hampshire primary, hoping that face-to-face politicking in the first-in-the-nation primary would pay off with a strong second-place finish or a surprise victory in Romney’s back yard. While other GOP candidates spent December in Iowa, the Huntsman campaign ignored its leadoff caucuses, where social conservatives were all but certain to give the Mormon from Utah short shrift.

Central to Huntsman’s New Hampshire strategy was its open Republican primary, which allowed independents to vote along with declared party members. He gambled that he could attract moderate voters, Republicans and independents alike, by presenting himself as successful conservative leader who wasn’t interested in engaging in a culture war.

He called his third-place showing a “ticket to ride” to South Carolina, but his distant finish behind Romney and runner-up Ron Paul was widely regarded as lackluster.

Huntsman, 51, was born in Redwood City, Calif., and raised in Utah. His father, an industrialist and at one time a Nixon administration official, founded Huntsman Chemical Corp. in 1982. Now the Huntsman Corp., it reported revenues of more than $9 billion in 2010.

The younger Huntsman drifted a bit as a young man. He attended high school in Salt Lake City but dropped out to play keyboards in a band. He later attended the University of Utah, then dropped out to serve two years as a Mormon missionary in Taiwan, where he learned to speak Mandarin.

He returned to the University of Utah in 1981 and later worked as an intern for Sen. Orrin Hatch, R-Utah, and as a staff assistant to President Ronald Reagan. He left college to join the Huntsman Corp. in 1983, the same year he married Mary Kaye Cooper. He studied international politics at the University of Pennsylvania, earning a bachelor’s degree in 1987.

While he served in the administrations of both George H.W. Bush – he was ambassador to Singapore in 1992 – and George W. Bush, Huntsman first won elective office in 2004 as Utah’s governor. He was re-elected by a 3-1 margin in 2008, then resigned the following year to be America’s top diplomat in China.

Huntsman and his wife have seven children, including one adopted from India and one adopted from China.